This part just retrieves the IP of the client who made the request. The doc says:
> IP information: Comma-separated list of one or more IPs; if your app receives requests directly from clients, then it should be the client's remote IP as detected by the your app's load balancer; if your app is behind another load balancer (for example, Amazon's ELB), this should contain the exact contents of the original X-Forwarded-For header.